• Akihiro Tsukada's avatar
    aacdec: add support for dual mono in Japanese DTV · c3c646a8
    Akihiro Tsukada authored
    Japanese DTV uses some non standard extensions in AAC audio.
    One example is 'dual mono', which combines two independent
    audio into one stereo stream, storing them in left and right channels
    respectively.  Historically, dual mono audio has been used for
    multi-lingual audio, one for local/native language, and another for english,
    and usually the "main" (local language) channel should be output without
    any user interactions.
    
    The frames of those dual mono audio are allowed to set
    ADTS channel_config field to 0, and just contain two SCE's *WITHOUT* PCE,
    which is a non standard extension by Japanese DTV standard.
    (ref. ARIB STD-B32 PartII 5.2.3)
    
    This patch adds an AVPacket side data, AV_PKT_DATA_JP_DUALMONO,
    which indicates that the AVPacket is likely to contain an audio frame
    with the above dual mono extension, and has the parameter to specify
    the desired channel selection in that case.
    It also makes aacdec to detect dual mono and output just the desired
    channel when this side data is attached.
    Signed-off-by: 's avatarAkihiro Tsukada <atsukada@users.sourceforge.net>
    Signed-off-by: 's avatarMichael Niedermayer <michaelni@gmx.at>
    c3c646a8
aacdec.c 104 KB